The present invention is directed to a golf ball and, more particularly, a golf ball comprised of a non-aqueous fluid or liquid center. Surrounding the center is a first layer and a second, solid, non-wound layer and a cover.
Generally, golf balls have been classified as solid balls or wound balls. Solid balls are generally comprised of a solid polymeric core and a cover. These balls are generally easy to manufacture, but are regarded as having limited playing characteristics. Wound balls are comprised of a solid or liquid filled center surrounded by tensioned elastomeric material and a cover. Wound balls generally have a good spin characteristics and feel when struck by a golf club, but are more difficult to manufacture than solid balls.
The prior art is comprised of various golf balls that have been designed to provide optimal playing characteristics. These characteristics are generally the initial velocity and spin of the golf ball, which can be optimized for various players. For instance, certain players prefer to play a ball that has a high spin rate for playability. Other players prefer to play a ball that has a low spin rate to maximize distance.
The prior art is also comprised of various liquid filled golf balls. Wound golf balls have been made with liquid centers for many years. Both U.S. Pat. Nos. 1,568,513 and 1,904,012 are directed to wound golf balls with liquid filled centers. U.S. Pat. Nos. 5,150,906 and 5,480,155, are directed to a hollow spherical shell of a polymeric material which is filled with a liquid or unitary, non-cellular material that is a liquid when introduced into the shell. The shell is disclosed as being the outer cover or an inner layer with the outer cover formed to the external surface thereof. The shell varies in thickness from about 0.060 to 0.410 inches in thickness.
Broadly, the present invention comprises a golf ball having a core and a cover in which the core is comprised of a non-aqueous liquid center surrounded by a solid portion. Preferably, the solid portion is comprised of a first layer surrounding the center and a second, solid, non-wound layer that is comprised of a thermoset rubber or thermoplastic elastomeric material. The solid portion of the core, preferably, has an inner diameter in a range of about 15 to 70% of the finished ball diameter and an outer diameter of about 80 to 98% of the finished ball diameter.
Still further, for a preferred golf ball having an outer diameter of approximately 1.68 inches, the first layer preferably has an inner diameter of approximately 0.25 to 1.18 inches and, more preferably, approximately 0.5 to 1.1. Most preferably, the first layer has an inner diameter of approximately 0.75 to 1.0 inches. The present invention is also preferably comprised of a second layer having an inner diameter in the range of 0.55 to 1.45 inches and, more preferably, having an inner diameter of approximately 0.8 to 1.3 inches. Yet further still, the present invention has a second layer having an outside diameter in the range of 1.3 to 1.65 inches and, more preferably, in the range of 1.45 to 1.62 inches. In the most preferred embodiment, the second layer has a radial thickness of about 0.2 to 0.3 inches.
More particularly, the invention is directed to a golf ball having a non-aqueous liquid filled center having a specific gravity and viscosity such that the performing properties of the ball, such as the moment of inertia, may be varied to achieve certain desired parameters such as spin rate, spin decay, compression, initial velocity, etc. Still further the fluid filled center preferably has a high specific gravity, i.e., greater than 1.2, for a high spin ball or a low specific gravity, i.e., less than 1.2 for a low spin ball.